


Miracle of Modern Engineering

by ChimaAmla



Category: Notice Me Senpai! (Video Game)
Genre: Anal Sex, For Science!, M/M, Polyamory, Robot Seiichi, Robot Sex, Robots, Size Kink, Sort Of, Threesome, Threesome - M/M/M, Voyeurism
Language: English
Status: Completed
Published: 2017-09-18
Updated: 2017-09-18
Packaged: 2018-12-31 04:10:08
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,345
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12124224
Author URL: https://archiveofourown.org/users/ChimaAmla/pseuds/ChimaAmla
Summary: Reiji's been working hard lately, but so have Shun and Seiichi - Reiji just doesn't know it yet.





	Miracle of Modern Engineering

The university lab was mostly quiet, still and silent except for the humming of a few machines and the scratching of Reiji’s pencil at one of the desks.  Reiji vaguely heard Seiichi step down from his charging station, crossing the tile toward him with barely a whir of mechanical joints, but the proof was almost done - a few more variables, and...

“Shun reiterates that he would like you finish on time today,” Seiichi said steadily from a few feet away.

“It’ll just be a few more minutes, I have to double-check a couple more things and then I’ll be on my way home,” Reiji tapped his pencil against his cheek without looking up, other hand knotted in his red hair to hold it back from his face.  Something was off in the equation, but he couldn’t figure out where.

“You’ve said that four times already,” Seiichi said politely, laying one elegantly-constructed hand across the papers.  “Shun is waiting for you, he has an experiment he wants to run.”

Reiji pushed back from the desk with a sigh, spinning in his chair and looking at Seiichi on every rotation.  More than six feet tall and constructed out of titanium alloys overlaid with plastic panels to protect the delicate wiring underneath, Seiichi was the prettiest android they’d made yet.  “He didn’t say he had anything planned.”

“It’s a surprise,” Seiichi said evenly, face still mostly impassive even after all the work they’d put in trying to figure out how to give him something like emotions.  He definitely  _ had  _ them, there were all sorts of new spikes in his RAM after they upgraded his code that couldn’t be accounted for any other way, but they just didn’t tend to translate onto his face.  When he clarified “From both of us,” though, that made Reiji stop and take notice.

“Oh?” a slow grin spread across Reiji’s face.  “Is it a sexy surprise experiment?”

“Hopefully,” Seiichi said, and then reached down and removed a panel from between his legs.  Reiji’s eyebrows went up at the odd divot in the protective structure covering Seiichi’s hip motors, and then the divot changed shape - first drawing into Seiichi’s body, making a  _ very _ soft and tantalizing-looking hole, and then pressed out again into the coolest sci-fi cock he’d ever seen.  It was pale white and soft purple like the rest of Seiichi’s protective coverings, and silicone gave it shape over...it had to be some kind of collapsible support struts, to be able to disappear away like they had at first and now fill it out to about twenty centimeters and…

Reiji was already grinning ear to ear, but now he laughed.  “You made it just a little bigger than Shun’s, didn’t you?”

“One does want to improve on the original,” Seichi actually managed a small smile at that, and Reiji almost danced in his seat.

“You prideful thing, ‘the creation has now surpassed the creator…’” he quoted, still snickering.  “It’s gorgeous, Seiichi. May I…?” he reached out halfway and paused, and Seiichi nodded his permission.  The silicone of his cock was soft and velvety, not skinlike at all but still  _ so _ touchable, and Reiji could feel the rounded supports inside.  “What are its specs?”

“Two hundred and eighty points each of tactile and temperature input, five hundred milliliters internal lubrication reservoir, length variance of negative twenty-five centimeters to thirty-five centimeters, thickness variance of two centimeters to ten centimeters.”  The synthetic cock changed shape and size in Reiji’s hand along with the descriptors, first shrinking and then growing until it was longer than his forearm and so big he couldn’t even close his hand around it.

Reiji’s mouth dropped open.  “Holy  _ shit, _ Seiichi.”

Seiichi’s cock settled back at its previous slightly-bigger-than-Shun’s size.  “This is the nature of the experiment Shun wished to run.”

Reiji sat back in his chair with a bewildered and amused grin, adjusting himself as his pants were suddenly just a bit too tight.  “What are the exact parameters of the experiment?”  he asked, even though he was pretty sure he already knew.

“Shun would like to know the maximum dimensions you are able to accommodate, and I volunteered to assist with the experiment.”

“Holy  _ shit,” _ Reiji whistled, leaning back in his seat.  “Fuck.  Okay.  Is Shun there?”

“Yes,” Seiichi said, blinking deliberately.  “He has full visual and audio input, for recreational and safety purposes, but has requested that I act independent of him unless otherwise directed.”

“You’re a filthy little voyeur, Shun,” Reiji said to Seiichi with a grin, knowing Shun could see and hear and was probably laughing like mad back in his room.

“He is,” Seiichi agreed, and Reiji broke down in giggles at the deadpan delivery.

“Okay, wow, fucking sweet, let’s do this,” Reiji said, standing and heading for the door, but Seiichi grabbed his arm.

Reiji turned back toward him, eyebrows raised.  “Power loads during tests exceeded optimal levels on internal battery systems,” Seiichi explained.

“You gotta be plugged in,” Reiji translated; he’d been wondering why Seiichi had still had the umbilical attached in the middle of his back.  Then Reiji smirked.  “Or maybe you just want to fuck in the lab.”

“Primarily the former,” Seiichi admitted, and gave a deliberate blink that was in time with the sound of the lab doors locking.

“See, that  _ should _ be freaky,” Reiji said, heading back to his desk and leaning against it.  He palmed himself through his pants as Seiichi moved in front of him, the two of them just barely not touching.

“You are known to show an affinity for situations which instill fear in the majority of the rest of the species,” Seiichi said, and Reiji proceeded to confirm it by stripping out of his lab coat and unbuttoning his shirt.

“You don’t gotta sweet-talk me, Seiichi, jeez, you’ll make a guy self-conscious,” Reiji said, but he was grinning and already dropping his pants without a bit of shame.  Seiichi might be able to pull out the big guns, but Reiji liked to think of himself as fun-sized, and that his littler cock just meant more excuses for custom sleeves and other toys.

As soon as he’d stepped out of his pants, Seiichi took him by the hips and lifted him easily up onto the desk with a quiet whir of motors.  Reiji  _ loved _ it when he did that - moving him like he was nothing at all, even though Seiichi was so slim he almost looked fragile, and his cock jumped at the thought that all that carefully-controlled force was here now with the sole intent of fucking him to the breaking point.

Seiichi stepped in close enough to line their cocks up against each other, his own reshaping to match Reiji’s size.  “I think you’re prettier than me,” Reiji murmured, circling his fingers around Seiichi’s now-little cock loosely.  Seiichi was mostly the same size all the way down, maybe a  _ little  _ thicker at the base, but at the tip he had just a little bit of a symmetrical bulge that was only barely reminiscent of a human cockhead - it looked more like an anal plug, and Reiji squirmed at the thought of it.  “So, lube?” he grinned up at Seiichi, and on command a bead of slick formed at the little slit at the end of the android’s cock.  Reiji grinned as it grew and dripped gorgeously a moment later, smearing it with his thumb.   _ “Damn, _ you’re a miracle of modern engineering, Seiichi.”

“As you enjoy telling me,” Seiichi said mildly as Reiji ground against him.  If Reiji hadn’t been listening for it as he wrapped a hand around both of them and started slowly jacking them off, he would’ve missed the slight kick up in the quiet whir of Seiichi’s cooling fans.

“How about we start small,” Reiji said lazily, trying not to let himself get too riled up too quickly.  “Two centimeters thick, since that’s the minimum, and...ten centimeters long,” Seiichi’s cock shrank slightly, and Reiji leaned back on the table to smear lube over his balls and back along his crack before guiding Seiichi down.  “Go in slow, but all the way.”

“Shun and I  _ did _ work on the process,” Seiichi said as he leaned over Reiji, cock pressing easily into Reiji’s hole - Reiji’s head fell back and he squirmed at the stretch, biting his lip on a grin at Seiichi’s subtle sass.  As soon as Seiichi was fully seated he rocked away and then thrust back in slowly, setting up a smooth rhythm, his hands resting on Reiji’s hips to hold him in place.

“Yeah, that’s it,” Reiji said, hiking his legs up to open himself up more.  “Okay,  _ haah,” _ he grinned across at Seiichi.  “All right.  Parameters for variable change,” he bit his lip and let out a small noise as one of Seiichi’s thrusts rubbed tight against his prostate.  “Command ‘deeper’, add one centimeter to length, comply?”

“Comply,” and Seiichi did, cock lengthening at just the right point in the stroke that Reiji almost didn’t feel it until Seiichi was bottomed out and suddenly filling him further than he’d been before.  Reiji squirmed and made himself focus.

“Command ‘more’, add one half-centimeter to thickness.  Comply?”

“Comply,” this time it was impossible to miss, no smooth outstroke to hide it as Reiji was suddenly stretched fuller.

“Fuck, wow,  _ cool,” _ Reiji breathed, voice a little bit shaky under his grin.  Seiichi was looking down at him with intense, cool detachment, and Reiji’s cock jumped.  They’d made Seiichi so damn  _ pretty, _ and he never stopped being glad for it.   _ “Fuck _ , ok, let’s get this show on the road.  Deeper,” Reiji grinned, and let his head fall back as he felt Seiichi’s smooth strokes get a little longer.  Every pull back brought him just to the edge of slipping out, and then he came all the way in again - and he was keeping the same pace, a smooth sine wave of friction and sensation that kept the wavelength but sped up to meet the higher amplitude.  “More,” and then Seiichi was thicker, and Reiji squirmed and panted. “Deeper,” Reiji whined and then Seiichi was there, that perfect size where he dragged across Reiji’s prostate on every thrust.

Reiji fumbled down to wrap fingers around his still-slick cock, pumping himself just a little faster than Seiichi’s agonizingly slow pace, and then Seiichi’s hand was on his wrist and pulling his hand away from himself.  Reiji opened his eyes and Seiichi was still staring down at him, but now as he calmly pinned Reiji’s hands at his sides.

“Shun wishes to see you come from penetration alone,” Seiichi explained, and Reiji squirmed under that inscrutable, focused gaze.

“It takes  _ forever,” _ Reiji whined, but tilted his hips to get that better angle anyways - Seiichi hadn’t changed pace at all,  _ fuck  _ this was going to be good.  “Can you speed up at all?” Reiji asked.

“I can,” Seiichi said, and then gave another one of those almost-there smiles and dragged his cock slow just once in just the right place that Reiji groaned.  “I will not.”

_ “Fuck,  _ I’ve made a horrible mistake, you’re an  _ evil _ robot,” Reiji laughed a little breathlessly, eyes squeezed shut to savor the feeling.  “Ok,  _ ah, _ current parameters, please.”

“Length is currently thirteen centimeters, thickness three centimeters,” Seiichi’s voice drifted into Reiji’s ears, and Reiji swore quietly.  Three centimeters thick and Reiji was already squirming, trying to pull his legs to make more room as Seiichi rocked impassively into him - and it wasn’t even a third as thick as he  _ could _ get

“Ok we’re,  _ hnn, _ let’s pick up the pace, yeah?” Reiji said, trying to focus.  “Reset command ‘more’ to increase by,” he squirmed, “by one centimeter on each command, and ‘deeper’ to increase by two centimeters on each.  Comply?”

“Comply,” Seiichi said mildly and then he was  _ bigger _ all of a sudden, knocking the breath out of Reiji and making him grab at the robot’s hips.   _ “Fuck _ fuck fuck  _ yes, more,”   _ Seiichi let himself slip most of the way out to thrust shallowly as he stretched Reiji open, and then he wasn’t hitting that perfect spot anymore, just shy, and Reiji panted and groaned.  “No, come on, don’t stop, deeperdeeperdeeper-” and then Seiichi was sliding in and in and  _ in  _ until Reiji could barely breathe, cock straining against nothing, so close to being too much.  “More,” Reiji gasped harshly, and it  _ ached,  _ stretched so open.  He panted up at the ceiling, hands grabbing at the edge of the desk so he could force himself down to try and take more of Seiichi’s cock.  “Deeper,” he said and it broke off in a groan on Seiichi’s thrust, come on, almost there, almost there -  _ “Deeper,” _ Seichi’s stokes were so long now they had to come quicker to keep the same pace, and it was right at that pace that felt  _ perfect, _ in time with the beat of Reiji’s blood,  _ “More,”  _ and then he was coming, so hard he couldn’t see, and he felt Seiichi spilling inside him and the liquid pressure of it only drew out the orgasm until it almost  _ hurt. _

Finally he felt Seiichi withdrawing, and it took Reiji an embarrassingly long time to realize that he wasn’t pulling away, just shrinking his cock to give Reiji room to come down.  Reiji just stayed splayed right where he was on the desk, head thrown back and gasping.

“Seiichi,” he panted without even opening his eyes, listening instead to the gradually-quieting whir of Seiichi’s cooling fans.  “What are the numbers?”

“Length upon orgasm: twenty-five centimeters,” Seiichi relayed dutifully.  “Thickness: seven centimeters.”  He slipped free and Reiji groaned, squirming at the emptiness and the slick dripping out of him.

_ “Fuuuuuck,”  _ Reiji breathed out slowly, raising a hand shakily to draw it through the come that painted halfway up his chest, before letting his hand flop back to the desk.

“Shun says you look gorgeous, and I am inclined to agree.”

“Thanks, Seiichi.”  He grinned openmouthed, heart still hammering in his chest.  “Ready for a second data point?  I think we can do better.”

**Author's Note:**

> Is this in Japan? The US? Some bizarre amalgamation of the two?? Who knows, I think we're probably all just here for the robofucking.
> 
> Check me out on [Twitter](https://twitter.com/ChimaAmla) and [tumblr](http://chimaamla.tumblr.com)!


End file.
